Antenatal corticosteroids for late small-for-gestational-age fetuses

Objectives: To compare neonatal morbidity in late preterm pregnancies with small-for-gestational-age fetuses, between those exposed and not exposed to antenatal corticosteroids (ACS). Methods: A retrospective study which included growth-restricted fetuses delivered at gestational week 34+0 to 36+6 weeks at a tertiary university-affiliated hospital, from March 2016 to March 2022. The primary composite outcome included the need for oxygen therapy or ventilation, respiratory distress syndrome, transient tachypnea of the newborn, bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular hemorrhage grade III/IV and neonatal mortality. Results: The primary composite outcome was comparable between those who did and did not receive ACS (26.1 vs. 20.8 %, p=0.512). Neonatal morbidity rates did not differ significantly between the groups, except for hypoglycemia, which was more common among neonates from ACS-exposed mothers (37.0 vs. 19.5 %, p=0.037). Multivariate analysis, adjusted for gestational diabetes and the mode of delivery showed no significant difference in the composite outcome between the groups (OR=2.03, 95 % CI 0.79-5.20, p=0.142). Cesarean delivery was associated with a higher risk of the primary outcome (OR=2.13, 95 % CI 1.17-3.85, p=0.013). After excluding those who did not receive the initial betamethasone dose within 2-7 days before delivery, the primary composite outcome remained similar between the groups. The primary composite outcome was similar among severely growth-restricted fetuses (<5th percentile) exposed and not exposed to ACS (29.2 vs. 22.0 %, p=0.560). Conclusions: Among preterm pregnancies complicated by small-for-gestational-age fetuses, ACS did not lower the rate of neonatal morbidity.